1. Field of the Invention
The invention relates to systems and methods for collecting medical video images of a patient and delivering the video images to a remote station. More specifically, the invention is directed to a system and method for transferring cardiac video images with negligible image degradation, archiving the images in long-term storage media, and providing a streaming multi-media video file that allows medical diagnosis and collaboration by doctors located outside the immediate treating hospital.
2. Description of the Related Art
Current advances in technologies related to compression, storage, and retrieval of digital video data are making their way into the medical field. These advances are making digital storage and display an economical means for hospitals and doctors to archive and review patient records. The scope of economic feasibility extends to cost, time, and image quality.
Traditional methods of archiving patient records involve substantial costs incurred from the physical media and allocating shelf space to store the same. Traditional paper and film storage methods require a significant amount of space, oftentimes requiring an entire filing room to store the accumulation of data. Newer digital methods of storing patient information require a system of removable high-capacity storage devices, such as tape drives, magneto-optical disk drives and recordable compact disks, which require a significant amount of cost and time to file and retrieve.
The time required to file and retrieve physical media in a storage facility is cumbersome, as a filing clerk is required to understand the filing structure, find the correct digitally recorded media, and then deliver the media to the diagnostician requesting the record.
Currently, archiving of patient video images is often performed with analog means, such as 35 mm black and white cine' film. Archiving and retrieving of such films are expensive and cumbersome. First of all, there is a significant cost associated with the chemicals required to develop the film. These chemicals must be kept at a specific temperature, and they break down over a short period of time. The chemicals must be replaced frequently, or there is a risk of compromising the quality of the medical image. This results in a higher cost for facilities with low volume. Secondly, this requires the creation and maintenance of a storage facility at optimum atmospheric conditions to preserve the film. Thirdly, the space required to store large numbers of film canisters takes up a significant amount of space. Hospitals would prefer to use this space for revenue generating purposes, such as patient rooms or labs. Finally, the process of reviewing a linear film to find a particular physiological event is time consuming.
In addition to cine' film, another method of recording analog video data is to incorporate a professional grade videotape recorder into the image acquisition system. A serious disadvantage of this method, like the cine' film, is the tedious searching along the linear videotape to find a specific physiological event a diagnostician wishes to view. Playback requires special commercial grade videotape players. These are expensive and are not typically available in each of the many locations in a building where a physician may wish to review the image data. This forces the physician to seek out the player. In a situation where the physician needs to consult the images before treating the patient, it is always possible he or she will be interrupted on the way back to the patient, thus affecting his or her retention of the image. Another inherent disadvantage is the physical size of the videotape and the storage area necessary to harbor large quantities of patient information. Still another disadvantage is the fact that any relevant patient demographic information is only available visually and does not allow electronic databasing for quick retrieval. Thus, videotape is not an ideal solution to storage and retrieval of medical video images. 
Many medical personnel have desired a digital means of archiving, searching, retrieving and viewing patient video data. There are current digital systems that allow digital video data to be recorded on transportable media such as magneto-optical or recordable optical compact discs. These systems provide transportable media with the ability to efficiently store large amounts of video data and methods for viewing the video images through a display device, such as a video monitor. However, there are still considerable drawbacks in current digital archiving systems.
An inherent problem associated with digital storage of medical video data is the file size that can be many megabytes per procedure. Files of these sizes can require a large amount of bandwidth, storage space, and memory. Thus, compression techniques become imperative when dealing with digitized video data. Image compression is usually accomplished in one of two ways. First is the intra-frame technique, wherein the compression takes place within each individual frame. Color depth may be reduced, image size altered, or resolution decreased to achieve an acceptable file size. An alternative method is the inter-frame compression technique, wherein compression is accomplished between frames. Multiple frames that do not significantly change from one to the next may be collapsed into a single frame that is then displayed during the time normally reserved for previous collection of frames.
In dealing with medical images, image quality is normally more important than file size. Unlike other types of multi-media applications, medical applications require detailed images since those images are often the basis for medical diagnoses. The original image quality is often termed lossless, denoting that there is no loss between the original image and the digitized version. Images that have undergone compression are labeled lossy images, denoting that some image quality has been lost due to compression. Many current compression techniques can slightly compress images with negligible image degradation. Unfortunately, the inherent sacrifice with compression is that as compression ratios are increased, image quality is decreased. Therefore, it is imperative that any compression results in negligible image degradation, and that the lossless images are immediately available for viewing.
Several systems have been implemented for compressing medical video images and then archiving them to digital media. One such system is disclosed in Lobodzinski, U.S. Pat. No. 5,619,995, which discloses a system for combining diagnostic digital motion video acquisition, display, and processing with physiological data indexing through utilization of techniques of digital motion video compression through domain transformation.
While some of the prior art systems allow for video storage, many of these systems require the doctor to have access to, or a copy of, the removable storage media. This is inefficient because without additional copies, only one physician can view the video data at a time, and viewing the data from a remote location requires video data media to be mailed or transmitted electronically such as through e-mail. This is a time consuming process that requires a large amount of storage space due to the large image file sizes. Moreover, either method of delivering video data to a remote location is critically deficient when a doctor must immediately diagnose a patient condition and does not possess the storage media or have the data saved locally on a computer.
Additionally, it may be desirous that organizations other than the hospital have access to patient video data. One such organization is a clinical research organization. Unfortunately, it is tedious and costly to make copies of digital video media and mail them to the various organizations requiring the patient video data.
What is needed is a system that provides physicians with a convenient way to view patient video data from remote locations. Additionally, it is desirous for a system to allow sharing of a single video data file from multiple locations simultaneously. Furthermore, a storage media that does not require a substantial amount of space or retrieval time would greatly enhance the benefits of digital archiving.